Accessible PDF documents for the blind

Written By: Peter Abrahams
Content Copyright © 2005 Bloor. All Rights Reserved.

There was a time when .pdf files were not accessible because screen readers, such as JAWS, could not interpret them. It is still true that the majority of .pdf files on the web cannot be read easily or correctly. Originally this was a problem with the tools that were used to create, and then read, the documents. Adobe recognised this as a moral, business and legal problem and has made significant steps to improve the situation, and the latest versions of Acrobat can create and process files that are accessible.

The latest proof of the giant steps made comes in the form of the Royal National Institute for the Blind (RNIB) annual report. This year is the first year that the report has been delivered in accessible PDF. The report is 70 pages and therefore Braille versions, or audio book versions, are cumbersome. The benefit of an accessible electronic version became apparent as I watched and listened to blind users reading and navigating around the document. The sheer joy of being able to read from the report and find the relevant sections quickly was obvious. So what made this document different from other PDF files? In brief:

  • The document is a searchable text file with imbedded fonts, not an image-only scan.
  • The document’s form fields are accessible.
  • The document structure (sections, headings, paragraphs etc.) is indicated by tags.
  • Reading order is clear and easy to follow.
  • Descriptive text is available for all graphics, links and form fields.
  • Navigation aids (links, bookmarks, table of contents etc) are included and easy to use.
  • The document language is defined as English making it easier for the screen reader to work correctly.
  • The security settings do not interfere with the screen reader.

The good news is that editorial staff at RNIB were able to produce an accessible document using the standard tools from Adobe. Two ticks to Adobe for producing the tools.

The bad news is that even an organisation as committed to accessibility as the RNIB found the process hard work. Specialists were drafted in to explain how to use the tools and how to ensure that the document was as accessible and as easy to use as possible. This was particularly true of tables which are some of the more difficult structures for a screen reader to navigate and render successfully.

Adobe provides several tools to help transform documents into accessible format. There are tools to take non-accessible documents and ‘repair’ them by adding tags or converting scanned images into text; however, the better answer is to start with an authoring tool that will automatically produce tagged documents. These are the tools that need to be used on the millions of non-accessible PDF files on the web today, so it is unlikely that they will be all fixed anytime soon. A crucial tool for the author is the accessibility checker that can be run against a document to see if it contains any accessibility issues. Like any automated checker it comes with the health warning that not all accessibility issues can be checked automatically – for example it cannot tell you that the picture of a gorilla should not have an alt tag of ‘the mother-in-law’. However, a clean bill of health from the checker is a very good indicator of high accessibility.

The final bit of good news is that the annual report shows that making a document accessible does not impact the visual presentation of the document; in fact a well designed accessible document has benefits for the normally sighted, such as:

  • Navigation via links.
  • Reflowing of text – enabling parts to be magnified without having to scroll left and right (click ctrl+4 when reading a PDF to see the results).
  • Hotkeys that for the expert user, and users with other disabilities, can be faster and more accurate than using the mouse.

Adobe has products that can produce accessible documents with a little effort and determination; they are also committed to make the process easier and more automatic. PDF files should definitely be an essential part of providing accessible information in the future.